1. In a bowl, combine the flour, baking soda, salt, sugar and cocoa powder.
2. In a separate bowl, whisk together the egg, oil and milk.
3. Place your bananas in a blender and add the water and peanut butter and mix until smooth.
4. Add the egg and banana mixture to the dry ingredients and stir well; then stir in the chocolate chips.
5. Spray muffin tins with cooking spray or line them with cupcake liners; then scoop out the batter until it is filled about 3/4 of the way to the top.
6. Bake at 350 degrees for approximately 15-20 minutes or until the top springs back when touched or when a toothpick comes out clean when inserted into the center.
7. Allow to cool on baking racks.